The removed of melamine (MA) was mainly performed by activated sludge adsorption instead of biodegradation.
High concentration of MA could not easily removal and had adverse impacts on biological wastewater treatment.
MA inhibited the enzyme activities of NOR, NR, NIR and PPX, which were closely relevant to nitrogen and phosphorus removal.
High MA concentrations promoted the metabolism of glycogen, thereby providing the advantage for the growth of GAOs.